#include "stdafx.h"
#include "code/md5engine.hpp"

namespace JHCPP
{
	namespace code
	{
		CMD5Engine::CMD5Engine()
		{
			m_digest.reserve(16);
			reset();
		}

		CMD5Engine::~CMD5Engine()
		{
			reset();
		}

		unsigned CMD5Engine::digestLength() const
		{
			return DIGEST_SIZE;
		}

		void CMD5Engine::reset()
		{
			std::memset(&m_context, 0, sizeof(m_context));
			m_context.count[0] = 0;
			m_context.count[1] = 0;
			m_context.state[0] = 0x67452301;
			m_context.state[1] = 0xefcdab89;
			m_context.state[2] = 0x98badcfe;
			m_context.state[3] = 0x10325476;
		}

		const CDigestEngine::Digest& CMD5Engine::digest()
		{
			static const unsigned char PADDING[64] = 
			{
				0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
			};
			unsigned char bits[8];
			unsigned int index, padLen;

			/* Save number of bits */
			encode(bits, m_context.count, 8);

			/* Pad out to 56 mod 64. */
			index = (unsigned int)((m_context.count[0] >> 3) & 0x3f);
			padLen = (index < 56) ? (56 - index) : (120 - index);
			update(PADDING, padLen);

			/* Append length (before padding) */
			update(bits, 8);

			/* Store state in digest */
			unsigned char digest[16];
			encode(digest, m_context.state, 16);
			m_digest.clear();
			m_digest.insert(m_digest.begin(), digest, digest + sizeof(digest));

			/* Zeroize sensitive information. */
			std::memset(&m_context, 0, sizeof (m_context));
			reset();
			return m_digest;
		}

		/* Constants for MD5Transform routine. */
		#define S11 7
		#define S12 12
		#define S13 17
		#define S14 22
		#define S21 5
		#define S22 9
		#define S23 14
		#define S24 20
		#define S31 4
		#define S32 11
		#define S33 16
		#define S34 23
		#define S41 6
		#define S42 10
		#define S43 15
		#define S44 21

		/* F, G, H and I are basic MD5 functions. */
		#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
		#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
		#define H(x, y, z) ((x) ^ (y) ^ (z))
		#define I(x, y, z) ((y) ^ ((x) | (~z)))

		/* ROTATE_LEFT rotates x left n bits. */
		#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

		/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
		Rotation is separate from addition to prevent recomputation. */
		#define FF(a, b, c, d, x, s, ac) { \
			(a) += F ((b), (c), (d)) + (x) + (UInt32)(ac); \
			(a) = ROTATE_LEFT ((a), (s)); \
			(a) += (b); \
				}
		#define GG(a, b, c, d, x, s, ac) { \
			(a) += G ((b), (c), (d)) + (x) + (UInt32)(ac); \
			(a) = ROTATE_LEFT ((a), (s)); \
			(a) += (b); \
				}
		#define HH(a, b, c, d, x, s, ac) { \
			(a) += H ((b), (c), (d)) + (x) + (UInt32)(ac); \
			(a) = ROTATE_LEFT ((a), (s)); \
			(a) += (b); \
				}
		#define II(a, b, c, d, x, s, ac) { \
			(a) += I ((b), (c), (d)) + (x) + (UInt32)(ac); \
			(a) = ROTATE_LEFT ((a), (s)); \
			(a) += (b); \
				}

		void CMD5Engine::updateImpl(const void* data, unsigned length)
		{
			const unsigned char* input = (const unsigned char*) data;
			unsigned int i, index, partLen;

			/* Compute number of bytes mod 64 */
			index = (unsigned int)((m_context.count[0] >> 3) & 0x3F);

			/* Update number of bits */
			if ((m_context.count[0] += ((UInt32) length << 3)) < ((UInt32) length << 3))
				m_context.count[1]++;
			m_context.count[1] += ((UInt32) length >> 29);

			partLen = 64 - index;

			/* Transform as many times as possible. */
			if (length >= partLen) 
			{
				std::memcpy(&m_context.buffer[index], input, partLen);
				transform(m_context.state, m_context.buffer);

				for (i = partLen; i + 63 < length; i += 64)
					transform(m_context.state, &input[i]);

				index = 0;
			}
			else i = 0;

			/* Buffer remaining input */
			std::memcpy(&m_context.buffer[index], &input[i],length-i);
		}

		void CMD5Engine::transform (UInt32 state[4], const unsigned char block[64])
		{
			UInt32 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

			decode(x, block, 64);

			/* Round 1 */
			FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
			FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
			FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
			FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
			FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
			FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
			FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
			FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
			FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
			FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
			FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
			FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
			FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
			FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
			FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
			FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

			/* Round 2 */
			GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
			GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
			GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
			GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
			GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
			GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
			GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
			GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
			GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
			GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
			GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
			GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
			GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
			GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
			GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
			GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

			/* Round 3 */
			HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
			HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
			HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
			HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
			HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
			HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
			HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
			HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
			HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
			HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
			HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
			HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
			HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
			HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
			HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
			HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

			/* Round 4 */
			II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
			II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
			II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
			II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
			II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
			II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
			II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
			II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
			II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
			II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
			II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
			II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
			II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
			II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
			II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
			II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

			state[0] += a;
			state[1] += b;
			state[2] += c;
			state[3] += d;

			/* Zeroize sensitive information. */
			std::memset(x, 0, sizeof(x));
		}

		void CMD5Engine::encode(unsigned char* output, const UInt32* input, unsigned int len)
		{
			unsigned int i, j;

			for (i = 0, j = 0; j < len; i++, j += 4) 
			{
				output[j]   = (unsigned char)(input[i] & 0xff);
				output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
				output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
				output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
			}
		}

		void CMD5Engine::decode(UInt32* output, const unsigned char* input, unsigned int len)
		{
			unsigned int i, j;

			for (i = 0, j = 0; j < len; i++, j += 4)
				output[i] = ((UInt32)input[j]) | (((UInt32)input[j+1]) << 8) |
				(((UInt32)input[j+2]) << 16) | (((UInt32)input[j+3]) << 24);
		}
	}//end of namespace code
}//end of namespace JHCPP
